Improved tracking of limb occlusion pressure for surgical tourniquets

Constant-pressure tourniquets are widely used to occlude blood flow into a patient´s limb to facilitate the performance of a wide variety of surgical procedures. Adaptive tourniquets that automatically adjust the cuff pressure to the minimum necessary for occlusion (limb occlusion pressure) as a function of the patient´s changing systolic blood pressure are expected to reduce the incidence of tourniquet-related injuries. However, these devices have not been widely used, largely due to problems in tracking the systolic blood pressure safely, accurately, and reliably in clinical environments with noise present. Initial lab trials and clinical trials compared the performance in tracking limb occlusion pressure during varying noise conditions of a typical oscillometric blood pressure monitor with that of a prototype system. The prototype system functions by detecting noise and rapidly estimating limb occlusion pressure using only data uncorrupted by noise. Results showed that the prototype consistently estimated limb occlusion pressure more rapidly, more accurately, and more reliably than the oscillometric monitor in noisy conditions typical of surgical procedures. The results also indicate that the prototype is feasible for incorporation into an adaptive tourniquet.